The Gandy/Klinowski paper appears to have an incorrect formula for the Z coordinate, or my Python program was doing something wrong.
Correcting the modulus squared to (97+0.24484) - 56 * mp.sqrt(3) seems to correct the problem, and all of the 12 patches meet up "perfectly".

Attached are the 12 python scripts for producing the 12 patches of a gyroid boundary surface.
The 12 scripts are the same, except for the ending 3 lines defining X, Y, and Z.
Input is gDomain.csv, created in MoI with SavePointNetwork script
Outputs are gNetP1.csv, gNetP2.csv, ...gNetP12.csv, placed in Desktop. (Adjust paths)
The 12 gNet__.csv files are input to a network of 22 curves in MoI, with the ImportPointNetwork script, run 12 times.
The 12 networks quickly individually Network to 12 surfaces.
The 12 surfaces quickly join to the gyroid boundary surface.

Next to be done is described in Table 2 of the paper, some mirrors and translations.
Eight boundary surfaces make up a triply periodic face-centered cubic unit cell of the G surface. This should be easy to accomplish in MoI.

- Brian